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All those buttons and dials on an SLR can be a little daunting. Everyone knows that you’re “supposed” to shoot in Manual mode, but it’s all rather complicated; yet another thing to think about when you’d rather be concentrating what’s in front of your camera.

It’s so easy to slip into the habit of using one of the Priority modes, or even Auto. I used Aperture Priority mode for the first couple years I had my camera, I loved it, I could choose the depth of field by adjusting the aperture and let my camera do the rest.

Then one day a lightbulb went off and I realised that shooting in Manual is only one little adjustment – two if you’re currently shooting in Auto. I challenged myself to shoot only Manual for a week and simply forgot to switch back. In fact when I was on a shoot a little while later I decided to use my old-faithful Aperture Priority to make it easier while I was shooting, the lack of my new-found control frustrated me so much I switched back to Manual and haven’t used anything else since!

This past few days has brought with it glorious sunshine. In England when the sun comes out, people go a little crazy, off come half the clothes, and everyone crowds onto the nearest patch of grass.

In my case my craziness reveals itself in my love for making things sparkle. I’ll take any excuse to create little shining stars across an image, the more or the bigger the stars, the better. To celebrate another beautiful summer morning, I thought I’d share a little tip to help you play with flare yourself.

ISO

Once your aperture has allowed your chosen amount of light into the lens, and the shutter speed has controlled the length of time the light has passed through the lens, the ISO controls how much of that light is absorbed.

The ISO is the camera’s measurement of light sensitivity. In analog photography, a higher ISO film absorbs the light faster, and film with a lower ISO number absorbs light more slowly. In digital photography it works in the same way, just with an electronic sensor in place of the film. A low number equals slower absorption.

Like both shutter speed and aperture, the ISO increases in stops that double or halve the light absorbed.

Standard digital ISO range

Some newer dSLRs have a higher range than this, but the principle is still the same. These stops correlate with the shutter speed and aperture stops. One ISO stop up or down equals one f/stop up or down, or one shutter speed stop.

Last week my friend and I were eating lunch in the park when a pair of Air Force helicopters roared through, the wind from their blades blowing bags off our bench.

By the time I’d pulled the camera from my bike panniers, the choppers were directly overhead. I clicked away until they were gone, then looked at my photos.

(Photo taken at 1/4000, f/5.6, ISO 800)

I confess that sometimes I’m rather lazy with my camera settings, thinking, “Ah well, I’ll fix it in Photoshop.” But after a month spent thinking and writing about creative exposures, the first thing I thought when I saw these photos was, “Oops.”

Aperture

The opening to the camera lens is called the aperture. You are able control the size of this opening, in increments known as f/stops, thereby choosing the amount of light you want to let through the lens and into the camera in one go. The f/stop numbers go from small; when the aperture is at its widest, to large; when the aperture is small.

To demonstrate, here is a lens aperture at f/2.8:

f/2.8

And here is an aperture at f/16:

f/16

While the shutter speed lets you chose how long the light enters the camera, the aperture lets you choose how much light is able to enter in that time. Closing the aperture is known as “stopping down”, while opening it is “stopping up”. Even though modern digital cameras generally have the ability to be set to 1/2-stops, or 1/3-stops, the range of full f/stops is still useful to be aware of because it corresponds to the standard range of shutter speeds (which is also more varied on modern cameras).

Histograms are a much misunderstood species, but can be an incredibly useful tool for any photographer and Photoshop artist. In my previous tutorial about clearing a colour cast I have already shown one example of how you can use these graphs; there are countless other ways they make themselves invaluable. And it’s not just in Photoshop that histograms are a useful guide. They can also be found in the display options of all digital SLR cameras, and most point-and-shoot cameras, and can be a useful aid in achieving correctly exposed photos.

I use them constantly while I’m working in Photoshop, so before I write any more tutorials that use these I’d like to give a quick explanation as to what it is you’re looking at, and why they’re so helpful.